The awful school shooting in Parkland, Florida on Feb. 14, where 17 young people were slaughtered by a sick and evil human being, was particularly vexing as there were so many warning signs — indications that the killer was planning his brutal act and capable of carrying it out.

Last year, there was a YouTube post under the shooter’s name that said: “Im [sic] going to be a professional school shooter.”

Additionally, police had responded to the gunman’s home 39 times over a seven-year period, according to documents released after the shooting. Full details are not yet available, but the nature of the emergencies at his home included “mentally ill person,” “child/elderly abuse,” “domestic disturbance” and “missing person.”

Worse, the FBI admittedly failed to investigate a warning that the shooter possessed a gun and planned to use it. A person who was close to the gunman called an FBI tip line on Jan. 5, several weeks before the shooting, to report concerns about him. The caller provided information about shooter’s gun ownership, desire to kill people, and disturbing social media posts, “as well as the potential of him conducting a school shooting.”

It’s obvious that our law enforcement agencies must do better, in the meantime, however, we need to figure out how best to protect our children from crazed shooters. Blanket gun control is a non-starter, and a ban on AR-15’s might feel good but is hardly a remedy. Teacher union leaders clamor for more guidance counselors. While that may be a good idea, we must do more.

Gun Violence Restraining Orders may help. GVROs permit a close relative or person living with a troubled individual to petition a court for an order enabling authorities to temporarily confiscate that individual’s firearms. In fact, California already has a GRVO statute on the books. Maybe now that it’s in the news, more people will become aware of it.

But there will always be someone who slips through the cracks and winds up on a school campus with a weapon ready for mayhem. At that point the FBI, GVROs and guidance counselors won’t be much help. The only thing to protect students from a crazed killer is a few teachers at every school packing a concealed firearm. After rigorous background checks and proper police-type training, these volunteers should be allowed to anonymously carry a concealed weapon on campus. And only the principal should know who the armed educators are.

Some may argue that many schools already have a “campus cop” and that is enough. But in Parkland, the armed security guard — for unexplained reasons — never entered the building to encounter the gunman. Also, many schools have sprawling campuses, and if a shooter manages to avoid the cop, students are unprotected. Hence, we need more than one person capable of defending them.

In fact many states already permit teachers to carry firearms on campus. According to the Education Commission of the States, Kansas, South Dakota, Tennessee, Texas, Oklahoma, Wyoming and several other states allow teachers, if certain conditions are met, to possess a concealed weapon on the job.

Other states are trying. In Virginia, Prince William County Board of Supervisors Chairman Corey Stewart wants trained teachers to have the option to carry concealed weapons during class.

Alabama state Rep. Will Ainsworth is also seeking a bill that would allow teachers to carry guns on campus. His proposed legislation lets public schools designate employees to undergo training and have concealed carry access.

Legislators in North Carolina and Maryland have comparable proposals in the pipeline.

Here in California, shortly after the Sandy Hook tragedy in 2012, Assemblyman Tim Donnelly proposed Assembly Bill 202, which would have provided for the training of educators in the use of concealed weapons. But it never had a chance in the state legislature. And this past October, Gov. Jerry Brown signed a law removing the rights of school administrators to decide whether an employee with a concealed weapon permit could bring a firearm on campus.

The notion that schools should be “gun-free zones” sounds good, but since evil-doers don’t play by the rules, the consequences can be devastating. On airplanes, armed marshals are placed anonymously on flights to safeguard us and our children. Also, after 9/11, willing pilots were trained by the TSA to carry weapons in the cockpits of commercial airliners. And presidents’ kids have armed secret service protection at their school. Don’t all of our children deserve the same?

Larry Sand, a retired teacher, is president of the California Teachers Empowerment Network.